Newcastle United's managing director, Derek Llambias, tells a story to illustrate the ordure he and the club's owner, Mike Ashley, endured before the club's sudden blossoming this season. While they were out and about with a friend from London, a van suddenly veered towards them, the driver rolled his window down, and hurled a volley of abuse at Llambias. His friend stopped, horrified. Llambias, though, had just kept walking, having barely registered it.

"We had so much of that, I don't hear it any more," Llambias smiles.

With Alan Pardew's team challenging for Champions League qualification, with a crucial appointment at Chelsea on Wednesday night, the Toon Army's contempt for Ashley, Llambias and others they scorned as the "Cockney Mafia" has been reappraised. It is now accepted that the period from Ashley's 2007 takeover – which saw him drinking and grinning with fans in the stands – to the 2009 relegation was a car crash for the club. Then and since – Llambias accepted what Ashley had promised would be "a horrible job" in May 2008 – three key episodes struck at the heart of what Newcastle fans have long held precious about their club.

First was the fallout with Kevin Keegan, a club legend, then last January's sale of Andy Carroll, that totem, a Geordie at No9. Just as it was starting to go right, in November the roof fell in, when they replaced the name of the hallowed St James' Park with Ashley's pile-it-high business, the Sports Direct Arena.

Yet the turnaround since, sparkling signings bought with the Carroll money, Pardew's air of authority and the cleaned-up finances, can make these moves look courageous now, by hard men prepared to be unpopular.

Llambias suggests that although Keegan walked out and won a constructive dismissal case which showed the club in an appalling light, he had not anyway believed that Keegan, the populist choice he inherited, was right for the modern role. Of Carroll, he says they did not want to sell until Carroll himself fancied the five-year deal Liverpool were offering. They dug in with Liverpool's then director of football, Damien Comolli, not to budge from £35m.

"They came in late, the day before deadline day [31 January 2011] which pushed the price up," says Llambias of Liverpool's approach. "We had no time to replace Andy, so they had to pay a premium." Liverpool were receiving £50m from Chelsea for Fernando Torres and were not prepared to run until the summer without a replacement. "The football side [Pardew and his staff] didn't want to sell him. But once he wanted to go, we all agreed to sell."

Llambias characterises Ashley, who can look a good-time Charlie with his replica shirt and lager, as in fact an obsessive business operator with a ferocious appetite for figures and the detail of an operation, who thrives on doing deals. Ashley floated Sports Direct for £1.9bn in 2007, sold shares for £1bn cash, still owns 70% and recently announced a profit of £100m last year.

After selling Carroll, they took waves of criticism. "We had a fan backlash, people asking where's the money gone, saying the £35m would never be spent," he recalls. "Then we did spend it all."

The £35m for Carroll, and the players spotted by chief scout, Graham Carr, signed with the proceeds, could be the best ever transfer dealing by a Premier League club. Demba Ba (free, from West Ham) arrived, Yohan Cabaye (£4.8m from Lille), Papiss Cissé (£9m from Freiburg), Davide Santon (£5m from Internazionale) and Gabriel Obertan (reported fee, £3m, from Manchester United). Two of this season's revelations, Hatem Ben Arfa (£2m from Marseille) and Cheik Tioté (£3.5m from FC Twente), were already there – some say their talents were repressed until the big British presences of Joey Barton and Kevin Nolan were moved on.

When he bought Newcastle in June 2007, the only English buyer in the wave of overseas takeovers, Ashley gave Sir John Hall and family a final payout of £53.4m for the stake they bought for £3m, and £38m to Freddy Shepherd and his brother, Bruce. Newcastle had been overspending for years; around £70m was owed in short-term debts, and the club made a £34m loss. The Halls and Shepherds had also earned prodigiously over the years in dividends and salaries. Ashley paid off all external debt, personally lending the money, now up to £140m, interest free. He has taken no money out of the club in five years.

After his initial foul-ups which propelled the club towards relegation, Ashley put the club up for sale, but Llambias says nobody with solid money made an approach.

"Then you reflect on where you are. There was a responsibility for us. Failure is not a word in Mike's vocabulary. So we decided to get back into it, and to be brave, to keep the core of the squad, add to it and try to bounce back."

They allowed for a £33m loss in 2009-10 to retain a squad good enough to win the Championship 11 points clear of second-placed West Bromwich Albion. Then, in December 2010, they invited vitriol again by sacking the manager who delivered it, Chris Hughton. Llambias maintains "great respect" for Hughton, who did "a fantastic job" at Newcastle and, Llambias adds, has done so again this season with Birmingham City in the Championship play-offs. However, he says he believed that Pardew had the "vision" they needed to "push forward".

He dismisses as nonsense, as Pardew has too, rumours which have gone around that Pardew had gambling debts, saying the manager does not gamble. Llambias is from the world of gambling, rising from dealing at blackjack and roulette tables to running casinos in Las Vegas and London. Between 1992 and 1998 he was managing director of Les Ambassadeurs, the Park Lane casino and hang-out for football dealers including Pini Zahavi and Kia Joorabchian. Llambias met Ashley when he opened Fifty, a casino club in Mayfair owned by the American, Robert Earl.

Llambias took his family to West Ham, and when Pardew won promotion with the Hammers in 2005, then took them to the FA Cup final the following season, Llambias says he was impressed.

Of St James' Park's rebranding, the next big row, Llambias supplies an explanation of surprising depth. He begins with an appreciation of fans' financial realities, rare among football executives who too often appear to think everybody is as comfortably off as them.

"There is not a lot of money in the north-east," he says. "The area relies heavily on public sector jobs and now the public sector is being cut." Seeing empty spaces at the ground, they did deals: a 10-year price freeze option, a 50% discount for the final 14 games for season ticket holders' friends and family, interest-free payment plans.

"People in the queues were telling me they couldn't afford it before, or that they couldn't afford to bring their kid too. We don't want empty seats."

While Hall famously invoked the plastic patriotism of a "Geordie nation", Llambias straightforwardly explains that the region's financial constraints mean they struggle to compete with the richer clubs.

He understands St James' Park is sacred, and that no major club's traditional home has ever had its naming rights sold.

But he argues that should not preclude them from making extra revenue to strengthen the club. There is a suggestion in his explanation that Sports Direct was used as a kind of buffer, to take the criticism and prepare supporters for the idea:

"Sports Direct is being used to showcase the naming rights opportunity to a global audience. It is about being able financially to put another Yohan Cabaye on the pitch."

The flak was torrential and many fans continue to resent the degree to which the old ground has become an advertising vehicle for the owner's company. All of which suggests again that Ashley and Llambias do not want for thick skins.

Having seen key decisions vindicated, and the club reducing its operating loss by almost £30m to £4m last year, Llambias says they do not have to sell players this summer, although with growing interest in the flourishing players including Tioté, he will not rule changes out: "We will continue to follow our financial and transfer model during the summer," is all he will say.

So after a season of exceeding expectations, even given Saturday's 4-0 defeat at Wigan on Saturday, anxiety at St James' Park is not wholly allayed. Pardew and his team are playing in fine harmony, but with Mike Ashley and Llambias now recognised not as maladroits but sharp operators who love a deal and are not scared to take flak, anything could happen next at the Sports Direct Arena.